1. Field of the Invention
The invention relates to a sampling tap apparatus in which a sample bottle is filled through a tap which includes a base and a pressure sensitive removable cap.
2. Description of Related Art
There are a number of known prior art approaches for tapping a fluid line. For example, a simple plug could be employed, but plugs tend to wear out rapidly and can be messy to use. A plug would pose a major problem if the materials being sampled were environmentally dangerous.
A second option might be to employ a second valve in a fluid sample line. Valves, however, also have the tendency to wear out and frequently get stuck in either the open or closed position if the materials employed are viscous.
One other possibility would be that if a flanged valve were used, a blind flange could be used to cap or seal off the outlet of the valve downstream from the process side of the system. A blind flange, however, would be somewhat impractical for a typical sampling application because there are generally four bolts that would have to be dealt with in order to remove or install a flange.
There are other problems with prior art approaches such as described above. If a 1/4" valve and a 1/4" pipe plug were placed together they might meet the requirements set out in the U.S. Clean Air Act (CAA). However, it would be difficult to install the device and then to remove the 1/4" pipe plug from the valve each and every time the sample had to be taken. Conversely, if two valves were used in series, it would still be necessary to add some sort of tube or pipe nipple that would direct the fluid flow into the sample bottle and the cost of that would probably exceed the cost of the present invention.
In addition to the foregoing, none of the prior art devices described above are especially responsive to pressure buildup inside the sample line. In other words, the effort to remove a plug or turn a valve according to the prior art techniques would be relatively independent of the pressure in the sample line. Accordingly, the operator would have no warning of potential dangerous pressure buildup.
In summary, the prior art does not appear to teach or suggest an inexpensive sample tap apparatus which includes a cap having reusable threads and which is sensitive to pressure buildup in the sample pipe.